Scaling of the specific heat and magnetization of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">YBa</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:ma

Jeandupeux, O.; Schilling, Andreas; Ott, H. R.; Otterlo, Anne van

doi:10.1103/physrevb.53.12475

Cited by 28 publications

(44 citation statements)

References 26 publications

(29 reference statements)

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“…Recently, detailed specific heat [6] and electrical conductivity [7] measurements very close to Tc revealed the effects of genuine critical fluctuations, described by the 3D-XY universality class. One important related question, addressed by several authors [8,9], concerns the robustness of the 3D-XY scaling against the application of a magnetic field. Indeed, in high enough magnetic fields the superconducting transition should be described by the lowest-Landau-Ievel (LLL) approximation of the Ginzburg-Landau (GL) theory [10,11].…”

Section: Introductionmentioning

confidence: 99%

Low-Field Fluctuation Magnetoconductivity in Bi2Sr2CaCu2O8 and YBa2Cu3O7: Gaussian, Critical and LLL Scalings

Pureur

Costa

1997

Fluctuation Phenomena in High Temperature Superconductors

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Section: Introductionmentioning

confidence: 99%

Low-Field Fluctuation Magnetoconductivity in Bi2Sr2CaCu2O8 and YBa2Cu3O7: Gaussian, Critical and LLL Scalings

Pureur

Costa

1997

Fluctuation Phenomena in High Temperature Superconductors

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“…Note that the analysis of Ref. 16 is not specific to the XY -model, the scaling forms that are used are quite general. Were the temperature scales T c and T MF to be well separated, XY critical scaling would presumably persist above T c .…”

Section: Specific Heatmentioning

confidence: 99%

“…Note, however, that this scaling form is not specific to the 3DXY -model. By plotting appropriate ratios of temperature-and field-derivatives of these scaling functions, one may extract directly the critical exponents of the system as the slopes of the quantitities being plotted, see for instance the very detailed analysis of this by Schilling et al 16 . It is conceivable that such a procedure would yield a curve with a kink in it when t > 0, as claimed to be observed by Schilling et al This in itself does not invalidate the 3DXY -scaling of high-T c cuprates.…”

Section: The Modelmentioning

confidence: 99%

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Phase coherence and the boson analogy of vortex liquids

Nguyen

Sudbø

1998

Phys. Rev. B

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The statistical mechanics of the flux-line lattice in extreme type-II superconductors is studied within the framework of the uniformly frustrated anisotropic three-dimensional XY -model. It is assumed that the externally applied magnetic field is low enough to invalidate the lowest Landaulevel approach to the problem. A finite-field counterpart of an Onsager vortex-loop transition in extreme type-II superconductors renders the vortex liquid phase-incoherent when the Abrikosov vortex lattice undergoes a first order melting transition. For the magnetic fields considered in this paper, corresponding to filling fractions f given by 1/f = 12, 14, 16, 20, 25, 32, 48, 64, 72, 84, 96, 112, and 128, the vortex liquid phase is not describable as a liquid of well-defined field-induced vortex lines. This is due to the proliferation of thermally induced closed vortex-loops with diameters of order the magnetic length in the problem, resulting in a "percolation transition" driven by non-field induced vortices also transverse to the direction of the applied magnetic field. This immediately triggers flux-line lattice melting and loss of phase-coherence along the direction of the magnetic field. Due to this mechanism, the field induced flux lines loose their line tension in the liquid phase, and cannot be considered to be directed or well defined. In a non-relativistic 2D boson-analogy picture, this latter feature would correspond to a vanishing mass of the bosons. Scaling functions for the specific heat are calculated in zero and finite magnetic field. From this we conclude that the critical region is of order 10% of Tc for a mass-anisotropy Mz/M = 3, and increases with increasing mass-anisotropy. The entropy jump at the melting transition is calculated in two ways as a function of magnetic field for a mass-ansitropy slightly lower than that in Y BCO, namely with and without a T -dependent prefactor in the Hamiltonian originating at the microscopic level and surfacing in coarse grained theories such as the one considered in this paper. In the first case, it is found to be ∆S = 0.1kB per pancake-vortex, roughly independent of the magnetic field for the filling fractions considered here. In the second case, we find an enhancement of ∆S by a factor which is less than 2, increasing slightly with decreasing magnetic field. This is still lower than experimental values of ∆S ≈ 0.4kB found experimentally for Y BCO using calorimetric methods. We attribute this to the slightly lower mass-anisotropy used in our simulations. 74.25.Dw, 74.25.Ha,74.60.Ec

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“…Since α in (1) is very small, and 1/2ν ≈ 0.75, the two predictions are rather hard to distinguish. Some authors claim that lowest-Landau-level scaling works just as well as, or indeed better than, critical point scaling [15][16][17][18][19][20][21]. For HgBa 2 Ca 2 Cu 3 O 8+δ [22], specific heat data appear to collapse to a common curve when plotted in the form of (1), but the scaling function C(x), which ought to be universal, is apparently rather different from that found for YBCO.…”

Section: Introductionmentioning

confidence: 98%

Critical-point scaling function for the specific heat of a Ginzburg-Landau superconductor

Lee

Lawrie

2001

Phys. Rev. B

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If the zero-field transition in high temperature superconductors such as YBa 2 Cu 3 O 7−δ is a critical point in the universality class of the 3-dimensional XY model, then the general theory of critical phenomena predicts the existence of a critical region in which thermodynamic functions have a characteristic scaling form. We report the first attempt to calculate the universal scaling function associated with the specific heat, for which experimental data have become available in recent years. Scaling behaviour is extracted from a renormalization-group analysis, and the 1/N expansion is adopted as a means of approximation. The estimated scaling function is qualitatively similar to that observed experimentally, and also to the lowest-Landau-level scaling function used by some authors to provide an alternative interpretation of the same data. Unfortunately, the 1/N expansion is not sufficiently reliable at small values of N for a quantitative fit to be feasible. 64.60.Fr, 74.25.Bt

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Scaling of the specific heat and magnetization ofYBa2Cu3

Cited by 28 publications

References 26 publications

Low-Field Fluctuation Magnetoconductivity in Bi2Sr2CaCu2O8 and YBa2Cu3O7: Gaussian, Critical and LLL Scalings

Low-Field Fluctuation Magnetoconductivity in Bi2Sr2CaCu2O8 and YBa2Cu3O7: Gaussian, Critical and LLL Scalings

Phase coherence and the boson analogy of vortex liquids

Critical-point scaling function for the specific heat of a Ginzburg-Landau superconductor

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